Scientific Anglers Sonar Tropical Custom Tip Fly Line Blue/Black WF-SFly anglers are nothing if not inventive. From splicing together lines to weighing coils on a digital scale, finding the perfect sinking line can be a chore. The SONAR Tropical Custom Tip sinking fly line makes all of that much, much easier. This cut to fit fly line allows you to slice off as much line as you need to fit everything from a 7 weight through a 15 weight. Cut to fit design lets you cut the tip to the ideal weight Goes deep and stays deep